Human study supports theory on why dengue can be worse the next time around

Amount of antibodies left over from first infection may boost chances of severe reaction the second time

SAMPLE TIME A boy in Managua, Nicaragua gives blood in June 2017 for an ongoing project examining dengue in children.

Paolo Harris Paz

Et tu, antibody? In humans, dengue can be more severe the second time around. Now, a study implicates an immune system treachery as the culprit.

The study suggests that the amount of anti-dengue antibodies a person has matters. In a 12-year study of Nicaraguan children, low levels of dengue antibodies left over in the blood from a prior infection increased the risk of getting a life-threatening form of the disease the next time around, researchers report online November 2 in Science.

Four related viruses cause dengue. The theory that antibodies protective against one type of dengue can collude with a different type of the virus to make a second infection worse was proposed in the 1960s. Such antibody-dependent enhancement has been shown in cells and lab animals. But “there’s been this controversy for five decades about, does this antibody-dependent enhancement really

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